It's about three-and-a-half times as heavy as a Human Brain
In other words, the weight of a Human Brain is 0.270 times 0.00000000500 megatonnes.(adult)
The average weight of an adult human brain is between 0.000000001350 megatonnes. In humans and primates, sight and vision utilize about 30 different parts of the brain which together account for about half of the brain's size.
It's about five times as heavy as a liter of Water
In other words, 0.00000000500 megatonnes is 4.999860 times the weight of a liter of Water, and the weight of a liter of Water is 0.20000560 times that amount.(fresh; 4° C / 39.2° F; maximum density)
Contrary to popular belief, 1 liter (0.0.264172052358148 gal) of water at 4° C / 39.2° F (its point of maximum density) weighs 0.0000000010000280 megatonnes rather than 1 kg exactly. The total volume of water on the planet Earth is about 13,590,000,000,000,000,000 (13.59 quntillion) L (3,590,000,000,000,000,000 gallons).
It's about one-fifth as heavy as a Dalmatian
In other words, 0.00000000500 megatonnes is 0.1690 times the weight of a Dalmatian, and the weight of a Dalmatian is 5.920 times that amount.(a.k.a. Dalmatinac, a.k.a. Carriage Dog, a.k.a. Spotted Coach Dog, a.k.a. Firehouse Dog) (FCI standard; male)
The Fédération Cynologique Internationale (FCI) calls for Dalmatians to weigh between 0.00000002950 megatonnes. The association of the breed with fire departments (and similarly with Budweiser Beer and its team of Clydesdales) stems from their affinity for horses, having been used historically as carriage dogs capable of guiding horse-drawn fire engines to the sites of blazes.
It's about eight times as heavy as a Basketball
In other words, 0.00000000500 megatonnes is 8.016809534 times the weight of a Basketball, and the weight of a Basketball is 0.124737901750 times that amount.(NBA official ball standards, Size 7)
A regulation NBA basketball, manufactured by Spalding, is known as a Size 7 ball and weighs 0.000000000623689508750 megatonnes. These balls have 4,118 pebbles each with a diameter of 2.5 mm
It's about one-tenth as heavy as a Toilet
In other words, 0.00000000500 megatonnes is 0.1150 times the weight of a Toilet, and the weight of a Toilet is 8.70 times that amount.(KOHLER Round front sitting flush toilet, model #K-11471-0)
The weight of a typical round front sitting flush toilet is 0.00000004360 megatonnes. The Indian town of Musiri in Tamil Nadu state features the world's only paying toilet, which rewards its users up to 10¢ Indian (10 paisas) per visit and uses the waste for compost and fertilizer.
It's about one-tenth as heavy as an Octopus
In other words, the weight of an Octopus is 10 times 0.00000000500 megatonnes.(for Giant Pacific Octopus, Enteroctopus) (Adult, average)
The adult North Pacific Giant Octopus usually weighs around 0.0000000500 megatonnes. It is the largest octopus species and is known for its considerable intelligence, including the ability to open jars, solve mazes, and mimic other octopuses.
It's about twelve times as heavy as a Football (Soccer)
In other words, the weight of a Football (Soccer) is 0.083 times 0.00000000500 megatonnes.(a.k.a. Soccer, a.k.a. Association Football) (FIFA Law 2 specification)
According to FIFA's Law of the Game number 2, a football must weigh between 0.000000000410 megatonnes and 0.000000000450 megatonnes. An artifact on display at the Smith Art Gallery in Museum in Stirling, Scotland is said to be the world's oldest football and is about one-third to one-half the size of a modern football.